Computing device



Feb. 19, 1952 D. D. EVERS 2,586,421

COMPUTING DEVICE Filed Aug. 25, 1945 3 Sheets-Sheet l 32 FIG Fla. 2

22 ,9 INVENTOR DUNDRED D. E VE R8 g MM- ATTORNEY Feb. 19, 1952 Filed Aug. 25, 1945 D. D. EVERS COMPUTING DEVICE 5 Sheets-Sheet 2' DUNDRED D. E VERS ATTORNEY Feb. 19, 1952 D. D. EVERS COMPUTING DEVICE 3 Sheets-Sheet 3 Filed Aug. 25, 1945 m u A m, A q mm ex A E mu mm A h x A NN Q Q\ 6? INVENTOR HUNDRED D. E VE RS ATTORNEY Patented Feb. 19, 1952 COMPUTING DEVICE Dundred D. Evers, La Jolla, .Qalifl, assignor to the United States of Americaas represented by the Secretary of theNavy Application August 25, 1945, Serial No. 612,677

1 Claim. (Cl. i i-9:13;?)

The present invention relates to the ball type of computing devices.

An object of the invention is the provision of an improved construction for the vball type of computing devices.

Another object is the provision of an improved and simplified construction of the ball type of resolving mechanisms for eliminating difficulties due to misalignment.

A further object is the provision of a simple improved mechanism for the direct and accurate addition of vector components.

In the ball-type resolver or Henrici harmonic analyzer, a ball is driven by a roller bearing :against a pole and the pressure of this driving :roller is balanced by the reaction of a guide roller at the opposite pole. Output rollers are arranged around the equator of the ball. The term equator is here intended to mean a great circle of the ball, all points on which are equidistant from the poles. The poles are the points at which the axis of the equator touches the surface of the ball. Operation of the driving roller causes the ball to rotate about the diameter that is parallel to the axle of the driving roller, which can be so positioned as to change the direction in which the ball turns. It is necessary to provide an arrangement for keeping the guidev roller axis parallel to that of the driving roller. Other,-

wise the effect of the two rollers is to forcethe ball to one side, that is, approximately in the direction of the axes of these two rollers, .and thereby to increase the force exerted against some of the equatorial rollers and to reduce that impressed on others. Heretofore, it has been necessary to impose high contact pressures on the out put rollers at the equator simply to prevent this lateral crowding of the ball from reducing the forces between ball and output rollers below the values required for good driving contact. This increased roller pressure increased the mechanical load on the device and thereby aggravated the difficulty. Additionally, prior-art devices also involve heavy gearing arrangements for aligning the axes of the guide and drivin rollers.

In accordance with my present invention I avoid these limitations of prior-art ballresolvers by employing a caster-type guide roller. Inthe construction described the guideroller ,is' incapable of exerting any lateral force on the ball, that is, any force in the direction of the guide roller axis. Consequently, no displacementreducing the forces on the equator rollers can occur.

.In accordance with the present invention I also provide an improved ball computer capable of reciprocal operation, in which the equatorial rollers are employed as drivers for introducing vector data components into the calculating de- .vice and the vector sum or solution is taken from a polar roller.

It will be understood that when the prior-art ball type of computer is operating in such fashion as to add two vectors and to determine the polar coordinates of the resultant, the equatorial rollers function as the driving rollers, one polar roller serves as the output roller, and the roller located in diametrical opposition to the output roller acts as a guide roller. The reaction of the guide roller balances the pressure of the output roller against the ball. Similarly, it is necessary to provide an arrangement for maintaining parallelism between the axes of the guide and output rollers. Otherwise, displacement of the ball would increase the force exerted on the ball by one of the driving rollers and reduce that exerted by the other. .In prior-art devices it has been necessary to impose high contact pressures between equatorial driving rollers and ball and to provide heavy gearing arrangements for aligning the axes ofthe guide and output rollers in order to prevent ball displacement from reducing the forces between ball and roller below those required for good driving contact. I avoid these limitation of prior-art devices by using casters at both poles. The trailing angle of a caster then indicates the vector angle or direction of the vector sumor resultant and the speed of rotation of a caster roller indicates its magnitude or modulus.

vOne ,applicationof this arrangement is in the computation of course (Ct) and speed (St) of a target for the control of naval gunfire. Certain prior systems for determining these quantities have employed trial and error methods in accordance with which values were assumed for course and speed and checked by the calculating devices. For example, a calculating device would determine the range rate (dB) and bearing drift (dBr) that should result from the assumed values of course and speed, Then the officer operating the equipment would compare these computed values withthe range rate and bearing drift actually observed and make further estimates for correcting: the values first assumed. The difiiculties and delays of such a process were aggravated by the circumstance that it was often difficult to determine which assumed quantity, whetherior vspeed or course, ought to be revised for the next calculation. The present invention overcomes these, difficulties because its method of calculation is-direct and automatic so that it may be employed in a system which requires no estimates of this character.

These and other objectives and advantages of the invention will be apparent from the following description taken in connection with the drawings in which:

Fig. l is a perspective view of a computing device embodying my present invention in a preferred form;

Figs. 2 and 3 are detail sectional views taken along line 2-2 of Fig. 3 and line 3-3 of Fig. 2, respectively;

Figs. 4 to '7, inclusive, are diagrams for explaining the operation of the device of Figs. 1 to 3;

Figs. 8 and 9 are elevation and plan views showing certain of the moving parts of a resolver embodying my invention; and

Fig. 10 is a mechanical schematic diagram of a computing system including the device illustrated in Figs. 1 to 3.

In Fig. 1 there is illustrated a device which vectorially adds two component quantities and determines the modulus or magnitude of the resultant vector quantity as well as the polar or vectorial angle of the resultant. A ball I has three rollers I2, I4 and I8 (Fig. 4) contacting it at its equator. All three rollers turn about horizontal axes. Rollers l2 and I4 are spaced 90 apart along the equator and constitute drivers by which velocity components are imparted to the ball. Roller I6 is an idler for holding the ball against the rollers I2 and I4.

As may be seen in Figs. 1 and 2 the ball ID has an upper caster-roller l8, and a lower casterroller 20, which contact it near the upper and lower poles respectively. The caster wheel I8 has a horizontal axle trunnioned in a bracket 22 which in turn is fixed to a trunnion bearing 24 the axis of which constructively passes through the center of the ball I0. Caster roller 22 is similarly supported so that the axis of its trunnion bearing constructively passes through the center of the ball. Trunnion bearing 24 carries a gear 26 which drives a plate or gear 28 that may be provided with an index (not shown) to indicate the angular position of the caster trunnion, that is, the direction in which the caster I8 trails. Gear 28 may also be used for transmitting this angle datum to other computing apparatus. This datum is the polar or vectorial angle of the resultant vector.

In order to indicate the modulus or magnitude of the resultant vector, which is determined by the speed of roller I8, any suitable conventional tachometer may be provided. For example, caster roller I8 periodicall actuate a microswitch 32 by means of a cam and plunger best shown in Figs. 2 and 3. Roller I8 carries a four-sided cam I9. Trunnion 24 is hollow and has a pair of bearlugs 25 to permit a pin 34 to slide up and down therein. At its lower end this pin 34 carries a rig-id arm 36 which rides cam I9, and at its upper end the pin drives against the operating plunger of the microswitch 32 the construction of which is shown, for example, in U. S. Patent No. 1,960,020. The switch actuates any suitable speed-indicating device (not shown).

Themotion imparted to the ball ID by the two driving rollers I2 and I4 consists of a rotation about a horizontal diameter and the consequent motion of the ball surface in the region of the upper pole will cause the caster roller I8 to trail in the direction of the plane of rotation. Accordingly, the rotated position assumed by the caster trunnion 24 indicates the direction of rotation of the ball. The caster roller 20 behaves similarly out of course will assume an opposite orientation, as shown in Fig. 1. Caster 20 is simply a guideroller for holding the ball against the upper caster roller I8. Since it is free to trail, the guideroller can roll freely on the ball ID for any direction of rotation that the two driving rollers I2 and I4 can give it.

The rotation of the roller I8 drives cam I9 which in turn cyclically lifts the pin 34 to operate the microswitch 32. The frequency meter 91 receiving electric impulses generated by the microswitch may be employed to provide an indication of the speed of roller I8 and therefore of the speed of rotation of the ball I0.

The diagrams of Figs. 4 and 5 show how the component speeds of rollers I2 and I4 add as vectors. As has already been pointed out, any surface speeds X and Y imparted to the ball I0 by the rollers I2 and I4 cause the ball ID to turn about some horizontal axis such as the axis 42 in Fig. 4. Accordingly, the track or path of contact of roller I2 on the surface of ball I0 is a circle which appears in projection as the dotted line 44 in Fig. 4 and similarly the track of roller I4 on the ball is a circle which appears in projection as the dotted line 46. The track of roller I8 is a circle which appears as the dotted line 48 and constitutes a great circle of the ball. For the purpose of this explanation the angular position of the caster trunnion is indicated by the angle T measured from the reference line 50. By inspection of the diagram it is clear that angle B equals Angle T and that angle A equals minus angle B. Accordingly, the ratio of the radius of circle 44 to the radius of the ball I0 equals the sine of A, which equals the cosine of T. Also the ratio of the radius of the circle 46 to the radius of the ball equals the sine of B, which equals the sine of T. Accordingly if X equals the surface speed of roller I2, Y the surface speed of roller I4, and Z the surface speed of caster roller I8, then X equals Z times the cosine of T, and Y equals Z times the sine of T. Therefore, the speeds of rollers I2 and I4 add vectorially as indicated in the parallelogram of Fig. 6. Their vector sum or resultant vector is the speed of caster I8. The vector angle of the resultant is the angle of trunnion 24. This speed and the angle fully indicate the polar coordinates of the resultant vector.

This relationship between the roller speeds, whereby velocity components are added, holds also for all other conditions and the resulting angular positions of the caster roller I8. For example, if the direction of rotation of roller I2 is the reverse of that indicated in Fig. 4, the conditions shown in Fig. 7 result. If it is kept in mind that the angle A is negative in Fig. 5, it will be seen that the same relations hold. The parallelogram of Fig. 7 corresponds to the conditions shown in Fig. 5.

Alternatively, the speed of caster roller I8 may be measured with gears and shafts, or by having the roller I8 drive a small electric generator 98 the voltage or frequency of which indicates the speed. However, since roller I8 turns in only one direction relative to bracket 22 a cam I9 such as is shown in Figs. 2 and 3 is generally satisfactory. Although the angle between the two rollers I2 and I4 is 90 in the specific construction illustrated in Figs. 1 to 3, it may be given other values to meet the needs of other computations.

Fig. 10 illustrates schematically a mechanical system, including the ball computer of Figs. 1

to 3, for computing the course (Ct) and speed (St) of a target ship. Observation of the target by other devices aboard ship produces two items of data: the bearing (Br) of the target from the observer, and the range (R) of the target, that is, its distance from the observer. Successive observations of range by still other devices aboard ship generate the range rate, (dR) that is, the speed in knots or other units at which the range decreases or increases.

Successive observations of bearing by the last named devices generate the bearing drift (aBr) in degrees per minute of time, or in other convenient units. The range rate and the rangetimes-bearing-drift (RdBr) constitute components of target velocity along the line of sight (Yt) and across it, (Xt) but they are components of velocity relative to the observers ship, so that in order to obtain the actual speed (St) and course (Ct) of the target, it is necessary to include also in the calculations the components of velocity of the observers shipalong (Y0) and across (X0) the line of sight to the target.

The Fig. system comprises: (1) a resolver having a mode of operation, reciprocal to that of the Figs. 1 to 3 embodiment but the same as that of the Figs. 8, 9 embodiment and including elements 68, 82, 64, 66, 68 and 18; four mechanical differentials 12, 74, 76 and I8; and a computer in accordance with the Figs. 1 to 3 embodiment, the same elements having the same reference numerals.

In Fig. 10 a ball 88 is driven at a speed proportional to that (So) of the observer's ship by a single driving roller 82, the angle of the axis of which is controlled by gears 64 and 66 in accordance with the relative bearing (Br) of the target, that is, the number of degrees of angle that the line of sight to the target lies oil the course of the observers ship. Driving roller 62 bears against a pole of the ball. Two output rollers 68 and 18 have their axes lying in the plane of the balls equator and bear against the ball at points 90 apart on the equator.

Roller 68 turns at a speed proportional to the component of observers velocity (X0) across his line of sight to the target. This rotation is combined in a difierential 12 with the product of range and the drift of true bearing (Rd Br), to supply to roller l2, the component of target velocity across the line of sight (Xt). Similarly, the speed of roller 10 is proportional to the component of observer's velocity (Yo) along the line of sight and is combined in dirferential 14 with the range rate (dR) to drive roller I4 at a speed proportional to the component of target velocity (Yt) along the line of sight.

Since the component speeds thus supplied to ball ID by the rollers I2 and I4 constitute the actual velocity components of the target along the line of sight and across it, the angle taken up by the caster roller I8 is the angle e between the target course and the line of sight (LOS) from the observer. The speed of roller I8 is proportional to the actual speed (St) of the target.

Relative bearing (Br) information is supplied not only to gear 66 but also to differential is where it is combined with observers course (Co) to provide true bearing (B) of the target, that is, the angle between line of sight and true north. Differential 18 then combines the true bearing (from differential 16) with the angle 6 between target-course and line of sight (LOS) (from gear 28) to provide target course (Ct) (as measured from true north).

Figs. 8 and 9 show a ball resolving mechanism embodying the present invention. A ball has three rollers 82, 84 and 86 engaging it at its equator, all three of which turn about horizontal axes. Rollers 82 and 84 are spaced apart along the equator and constitute output rollers from which the velocity components resolved by the mechanism are taken off. Roller 88 is an idler for holding the ball firmly against the rollers 82 and 84.

At the upper pole or top of the ball 88 is a driving roller 88 whose shaft 88 is trunnioned in a ring 98. This ring turns about an axis which constructively passes through the center of the ball 80 to swing the axis of the roller 88 while keeping it perpendicular to; the polar diameter of the ball. Ring 98 is rotated by a gear 9|. Fixed to the same shaft 89 as roller 88 is a bevel gear 92 which is driven by a second bevel gear 83. Gear 93 is centered with respect to ring 98 so as to drive the roller 88 regardless of the orientation of its axle 89. Supporting the ball 80 at its lower pole is a caster guide-roller 94, the trunnion axis 96 of which constructively passes through the center of the ball 80.

In operation, the roller 88 is driven at a speed proportional to the magnitude of the vector (such as So) that is to be resolved into rectangular components, and the angles that its axle 89 makes with the axes of the rollers 82 and 84 are set equal to the angles by adjustment of ring 90 (such as Br and 90Br) between that vector and the direction axes of the reference frame of cartesian coordinates in which the components are to be taken. The rotation of the ball 80 then drives output rollers 84 and 82 at speeds proportional to the required velocity-components (such as S0 sin Br or X0 and So cos Br or Yo). The caster 84 turns freely in its trunnion 96 and therefore trails freely.

It will be noted that elements 60, 62, 64, 66, 68 and Hi schematically represented in Fig. 10 correspond respectively, to elements 80, 88, 88, 90, 9|, 84 and 82 illustrated in Figs. 8 and 9.

It is thus seen that my invention provides simple and reliable mechanism for resolving a vector into its rectangular components or for adding vector components and obtaining the magnitude and direction of their sum, It will be apparent that the invention is not limited to any specific embodiment but rather is capable of many modifications and variations and is limited only in accordance with the scope of the priorart and the appended claim.

I claim:

In a computing device for determining the magnitude and direction of the vector quantity which is the resultant of two rectangular component vector quantities, a ball, a plurality of rollers rotatable about axes lying in an equatorial plane of the ball and having rolling engagement with the ball at spaced sections of an equatorial line defined by the intersection of said plane with the surface of said ball, two of said equatorial rollers having their axes disposed in perpendicular directions and constituting input rollers provided with drive means for imparting rotation to the ball at rates commensurate with the magnitudes of said component vector quantities, two casters supported for rotation about the polar axis normal to said equatorial plane, said casters having their roller axes laterally offset from their caster axes and having their rollers trailing in rolling engagement with the ball at opposite polar regions surrounding said polar axis, means connected to one of said casters for indicating 7 the direction of trail of said caster and thus the direction of said vector quantity to be determined, driven means, and means transmitting rotary motion from one of said caster wheels to said driven means to drive said driven means at a rate commensurate with the magnitude of said vector quantity to be determined.

DUNDRED D. EVERS.

REFERENCES CITED UNITED STATES PATENTS Name Date Jordan Mar. 26, 1895 Number Number Number Name fiate Samohod Dec. 8, 1896 Davison Mar. 5, 1901 Innes Feb. 12, 1918 Mengden Feb. 12, 1929 Avery June 19, 1934 House Dec. 6, 1938 House Dec. 6, 1938 Neweil Dec. 10, 1946 FOREIGN PATENTS Country Date France Mar. 5, 1935 Great Britain Nov. 16, 1922 Switzerland Oct. 2, 1939 Switzerland Jan. 16, 1942 

